Ink compositions

ABSTRACT

An ink comprised of (1) a liquid aldehyde, a liquid acid, or mixtures thereof, (2) a solid additive aldehyde compound, a solid additive acid compound, or mixtures thereof, (3) a lightfastness UV absorber, (4) a lightfastness antioxidant, and (5) a colorant.

REFERENCE TO COPENDING PATENT APPLICATIONS

This application is a continuation of application Ser. No. 08/935,929,filed Sep. 23, 1997, now U.S. Pat. No. 5,931,995. Hot melt inks areillustrated in U.S. Pat. No. 5,683,312, U.S. Pat. No. 5,667,568, U.S.Pat. No. 5,700,316, U.S. Pat. No. 5,747,554, and U.S. Ser. No. 641,866(D/95458), the disclosures of each being totally incorporated herein byreference.

Hot melt inks are also disclosed in copending applications U.S. SerialNos. 08/933,914, 08/935,889, 08/935,639 and 08/936,084 the disclosuresof each application being totally incorporated herein by reference intheir entireties.

A number of the components of the copending applications, such as thecolorants, ink additives, and the like may be selected for the inks ofthe present invention in embodiments thereof.

BACKGROUND OF THE INVENTION

The present invention is directed to ink compositions and, morespecifically, the present invention relates to semi-solid hot melt inkswith for example, a melting point of from between about 25° C. andabout, 50, preferably to about 40° C., especially useful for acousticink printing, processes and apparatuses, reference, for example, U.S.Pat. No. 5,121,141, U.S. Pat. No. 5,111,220, U.S. Pat. No. 5,128,726,U.S. Pat. No. 5,371,531, the disclosures of which are totallyincorporated herein by reference, including especially acoustic inkprocesses as illustrated in a number of the aforementioned copendingapplications and patents, such as an acoustic ink printer for printingimages on a record medium.

The inks of the present invention in embodiments thereof are comprisedof (1) a liquid non-aqueous vehicle with a boiling point of higher thanabout, or about equal to 150° C. and lower than about, or about equal to350° C., and more specifically from about 175 to about 325 degreesCentigrade, and yet more specifically from about 225 to about 300degrees Centigrade, and with a low acoustic loss to for example, reduce,or minimize energy consumption, and which acoustic loss is below, orabout equal to 60 dB/mm, (2) a solid additive that can be contained inthe ink, or a substrate, such as paper pores and with a melting point oflower than about, or equal to about 75° C. and preferably between about35 to about 74° C. and with a low acoustic loss to reduce, or minimizeenergy consumption, and which acoustic loss is for example, below about,or equal to about 100 dB/mm, (3) a light fastness UV absorber, (4) alight fastness antioxidant, (5) and a colorant such as a dye, a pigmentor mixtures thereof. More specifically, the present invention isdirected to semi-solid hot melt acoustic ink compositions comprised of(1) nonaqueous liquid vehicles having a boiling point higher than about150° C. and lower than about 350° C., preferably between about 170 toabout 300° C., and with low an acoustic loss below about 60 dB/mm, andpreferably in the range of from about 5 to about 40 dB/mm, (2) anonaqueous solid additive with a melting point of lower than about 75°C. and preferably between about 35 and 74° C., with a low acoustic lossbelow about (throughout below, and higher include about equal to also)100 dB/mm, and preferably in the range of from about 25 to about 80dB/mm, (3) a UV absorber, (4) an antioxidant, (5) a colorant, andwherein there can be generated with such inks excellent developed imageson plain and coated papers with acceptable image permanence, excellentprojection efficiency on transparencies without a post fusing step, andexcellent crease resistance, and wherein the inks possess acceptable,and in embodiments superior lightfastness, and superior waterfastness.Moreover, in embodiments of the present invention there is enabled theelimination, or minimization of undesirable paper curl since water neednot be present in the invention inks, and it is preferred that there bean absence of water, and since water is not present in the inks a dryercan be avoided thereby minimizing the cost of the acoustic ink jetapparatus and process.

PRIOR ART

In acoustic ink printing, the printhead generates for example,approximately 2.2 picoliter droplets by an acoustic energy process. Theink under these conditions should preferably display a melt viscosity ofabout 5 to about 20 centipoise or less at the jetting temperature.Furthermore, once the ink is jetted onto the paper, the ink image shouldbe of excellent crease property, and should be non-smearing waterfast,of excellent transparency and excellent fix qualities. In selecting anink for such applications, it is desirable that the vehicle display alow melt viscosity, such as from about 1 centipoise to about 25centipoise in the acoustic head, while also displaying solid likeproperties after being jetted onto paper. Since the acoustic head cantolerate a temperature up to about 180° C., and preferably up to atemperature of from about 140° C. to about 160° C., the vehicle for theink should preferably display liquid like properties, such as aviscosity of from about 1 to about 10 centipoise at a temperature offrom about 75° C. to about 165° C., and solidify or harden after jettingonto paper such that the ink displays a hardness value of from about 0.1to about 0.5 millimeter, which hardness is determined by a penetrometeraccording to the ASTM penetration method D1321.

Ink jet printing processes that select inks that are solid at roomtemperature and liquid at elevated temperatures are known. For example,U.S. Pat. No. 4,490,731, the disclosure of which is totally incorporatedherein by reference, discloses an apparatus for dispensing certain solidinks for printing on a substrate such as paper. The ink dye vehicle isusually selected with a melting point above room temperature so that theink which is melted in the apparatus will not be subject to evaporationor spillage during periods of nonprinting. The vehicle selectedpossesses a low temperature to permit the use of the solid ink in athermal ink jet printer. In thermal ink jet printing processes employinghot melt inks, the solid ink is melted by a heater in the printingapparatus and utilized as a liquid in a manner similar to that ofconventional thermal ink jet printing. Upon contact with the printingsubstrate, the molten ink solidifies rapidly, enabling the dye to remainon the surface instead of being carried into the paper by capillaryaction, thereby attempting to enable higher print density than isgenerally obtained with liquid inks. Hot melt ink jets are somewhatsimilar to thermal ink jets, however, a hot melt ink usually contains nosolvent. Thus, rather than being liquid at room temperature, a hot meltink is typically a solid or semi-solid possessing a wax-likeconsistency. These inks usually need to be heated, for example, toapproximately 100° C. before the ink melts and is converted into aliquid. With hot melt inks, a plurality of ink jet nozzles are providedin a printhead. A piezoelectric vibrating element is located in each inkchannel upstream from a nozzle so that the piezoelectric oscillationspropel ink through the nozzle. After the hot melt ink is applied to thesubstrate, the ink is resolidified by freezing on the substrate.

One advantage of thermal ink jets is their compact design for theintegrated electronics section of the printhead. Thermal ink jets aredisadvantageous in that the thermal ink has a tendency to soak into aplain paper medium. This can blur the print or thin out the printlocally thereby adversely affecting print quality. Problems have beenencountered with thermal ink jets in attempting to remove from the inkmoisture in a rapid manner so that the ink does not soak into a plainpaper medium.

One advantage of a semi-solid hot melt ink jet is their ability to printon coated substrates such as coated papers and overhead transparenciesyielding photographic quality images, since for example, the semi-solidhot melt ink quickly spreads on the surface of the coated paper andtransparencies.

In addition, U.S. Pat. No. 4,751,528, the disclosure of which is totallyincorporated herein by reference, discloses a semi-solid hot melt inkjet system which includes a temperature-controlled platen provided witha heater and a thermoelectric cooler electrically connected to a heatpump and a temperature control unit for controlling the operation of theheater and the heat pump to maintain the platen temperature at a desiredlevel.

Further, U.S. Pat. No. 4,791,439, the disclosure of which is totallyincorporated by reference, discloses an apparatus for use withsemi-solid hot melt inks having an integrally connected ink jet head andreservoir system.

Ink compositions for ink jet printing are known. For example, U.S. Pat.No. 4,840,674, the disclosure of which is totally incorporated herein byreference, discloses an ink composition which comprises a major amountof water, an organic solvent selected from the group consisting oftetramethylene sulfone, 1,1,3,3-tetramethyl urea, 3-methyl sulfolane,and 1,3-dimethyl-2-imidazolidone, which solvent has permanentlydissolved therein spirit soluble dyes.

U.S. Pat. No. 5,006,170 and U.S. Pat. No. 5,122,187, the disclosures ofeach of which are totally incorporated herein by reference, disclosesemi-solid hot melt ink compositions suitable for ink jet printing whichcomprise a colorant, a binder, and a propellant such as hydrazine,cyclic amines, ureas, carboxylic acids, sulfonic acids, aldehydes,ketones, hydrocarbons, esters, phenols, amides, imides, halocarbons, andthe like. The inks of the present invention are dissimilar than theaforementioned '179 and '187, in that, for example, the inventionvehicle selected displays an important acoustic loss value and aviscosity of from about 1 to about 20, and preferably about 10centipoise when heated to a temperature of from about 125° C. to about165° C., such that acoustic energy in the printhead can eject an inkdroplet onto paper.

U.S. Pat. No. 5,041,161, the disclosure of which is totally incorporatedherein by reference, discloses an ink jet ink which is semisolid at roomtemperature.

U.S. Pat. No. 4,853,036 and U.S. Pat. No. 5,124,718 disclose an ink forink jet recording which comprises a liquid composition essentiallycomprising colorant, a volatile solvent with a vapor pressure of 1millimeter Hg or more at 25° C., and a component that is solid at roomtemperature and having a molecular weight of 300 or more.

SUMMARY OF THE INVENTION

While the known ink compositions and processes may be suitable for theirintended purposes, a need remains for acoustic semisolid hot melt inkcompositions suitable for thermal ink jet printing. In addition, thereis a need for semi-solid hot melt ink compositions which are compatiblewith a wide variety of plain papers and generate photographic qualityimages on coated papers. Further, there is a need for semi-solid hotmelt ink compositions which generate high quality, lightfast, andexcellent waterfast images on plain papers. There is also a need forsemisolid hot melt ink jet ink compositions which generate high quality,fast-drying images on a wide variety of plain papers at low cost withhigh quality text and high quality graphics, and wherein the colorant,such as the dye is retained on the paper surface while the ink vehiclecan continue to spread within the paper structure. Further, there is aneed for semisolid hot melt ink jet ink compositions which exhibitminimal feathering. Additionally, there is a need for semi-solid hotmelt ink jet ink compositions which exhibit minimal intercolor bleed.There is also a need for semi-solid hot melt ink jet ink compositionswhich exhibit excellent image permanence. Further, there is a need forsemi-solid hot melt ink jet ink compositions which are suitable for usein acoustic ink jet printing processes. Additionally, there is a needfor semi-solid hot ink compositions suitable for ink jet printingprocesses wherein the substrate is heated prior to printing and iscooled to ambient temperature subsequent to printing (delay printingprocesses). There is also a need for ink compositions suitable for inkjet printing wherein high optical densities can be achieved withrelatively low dye concentrations. A need also remains for inkcompositions suitable for ink jet printing wherein curling of thesubstrate, such as paper, subsequent to printing is minimized, oravoided. These and other needs can be achievable with the inks of thepresent invention in embodiments thereof.

Examples of object of the present invention include, for example:

It is an object of the present invention to provide semi-solid hot meltink compositions with many of the advantages illustrated herein.

It is another object of the present invention to provide semisolid hotmelt ink compositions suitable for acoustic ink jet printing.

It is yet another object of the present invention to provide semi-solidhot melt ink compositions which are compatible with a wide variety ofplain papers and yield photographic quality images on coated papers.

It is still another object of the present invention to providesemi-solid hot melt ink compositions which generate high quality imageson plain papers, and wherein there is selected a dye, or wherein the inkvehicle contains acid, or aldehyde functionalities.

Another object of the present invention is to provide semisolid hot meltink jet ink compositions comprised of a dye and vehicle comprised of anacid, an aldehyde, and mixtures thereof and wherein in embodiments theinks possess a low viscosity of, for example, from about 5 to about 10at 160° C.

Yet another object of the present invention is to provide hot ink jetink compositions which exhibit low viscosity of from about 1 to about 10centipoise at a temperature of from about 125° C. to about 160° C.

Still another object of the present invention is to provide semi-solidhot melt ink jet ink compositions which exhibit minimal intercolorbleed.

It is another object of the present invention to provide semisolid hotmelt ink jet ink compositions which exhibit excellent waterfast,lightfast image permanence.

It is yet another object of the present invention to provide hot ink jetink compositions that contain no water and which are suitable for use inacoustic ink jet printing processes.

It is still another object of the present invention to provide hot inkcompositions that contain no water, or minimal water, and that aresuitable for ink jet printing processes wherein the substrate is heatedprior to printing and is cooled to ambient temperature subsequent toprinting (heat and delay printing processes).

Another object of the present invention is to provide ink compositionssuitable for ink jet printing wherein high optical densities can beachieved with relatively low dye concentrations.

Yet another object of the present invention is to provide water-freesemi-solid hot melt ink compositions suitable for ink jet printingwherein curling of the substrate subsequent to printing is minimized.

Another object of the present invention resides in the provision ofsemi-solid hot melt inks wherein the viscosity of the ink is from about1 centipoise to about 10 centipoise at, for example, the jettingtemperature which can be from about 125° C. to about 180° C., andpreferably from 125° C. to about 160° C. thereby enabling excellentjetting at reasonable power levels.

Further, in another object of the present invention there are providedsemi-solid hot melt inks with substantially no water and vehicles suchas an acid or an aldehyde vehicle and a colorant such as a dye, or apigment.

Additionally, in another object of the present invention there areprovided semi-solid hot melt inks with no water for ink printing methodsand apparatuses, and wherein a number of the advantages as illustratedherein are achievable.

The present invention relates to an ink composition comprised of (1) aliquid aldehyde and/or an acid vehicle with for example, anacoustic-loss value of from about 5 to about 40 dB/mm, and a boilingpoint between about 170 and about 300° C., (2) a solid additive with forexample a melting point of less than, or equal to about 75° C., andpreferably between about 35 and about 74° C., and with a low acousticloss of equal to about, or below about 100 dB/mm, and preferably in therange of from about 25 to about 75, a UV absorber, (5) a colorant, whichink has an acoustic-loss value of from about 10 to about 80 dB/mm,possesses a viscosity of for example, of from about 1 centipoise toabout 10 centipoise at a temperature of for example, from about 125° C.to about 165° C. Embodiments of the present invention include an inkcomposition comprised of (1) a liquid aldehyde, a liquid acid, ormixtures thereof, (2) an aldehyde compound, a an acid compound, ormixtures thereof, (3) a lightfastness UV absorber, (4) a lightfastnessantioxidant, and (5) a colorant.

DETAILED DESCRIPTION OF THE INVENTION

In embodiments the ink compositions of the present invention comprise acolorant, such as a pigment, a dye, or mixtures thereof, and a liquidvehicle with an acoustic-loss value of less than about, or equal toabout 60 dB/mm, and preferably between about 5 to about 40 dB/mm, and aboiling point of greater than, or equal to about 150° C., preferablybetween about 170 and about 300° C. and a solid additive, which additivefor example, evens the surface of paper so that the colorant, such asthe dye does not substantially penetrate into the fibers of the paper,and which additive possesses a melting point of lower than, or equal toabout 75° C. and preferably between about 35 and about 74° C., anacoustic-loss value of less than about, or equal to about 100 dB/mm andpreferably between about 25 to about 80 dB/mm. Mixtures include forexample from about 1 to about 99 parts or percent of one component, andfrom about 99 to about 1 percent, or parts of a second component.

The liquid aldehyde or the liquid acid vehicle with for example aboiling point of higher than about 150° C. and preferably between about170 and about 300° C. and with an acoustic-loss value of from about 5 toabout 40 B/mm is present in the ink composition in a suitable amount,for example, in an amount of from about 55 to about 1 percent by weight,the solid additive with a melting point of between about 35 to about 74°C., and having an acoustic-loss value of below about 100 dB/mm andpreferably from about 25 to about 80 dB/mm is present in an amount offrom about 5 to about 97 percent by weight, the UV absorber is presentfor example, in an amount of from about 10 to about 0.5 percent byweight, the antioxidant is present for example, in an amount of fromabout 10 to about 0.5 percent by weight, and the colorant is present inan amount of for example, from about 20 to about 1, and preferably fromabout 2 to about 12 percent by weight. The ink compositions containing(1) a low acoustic-loss vehicle, (2) a solid additive, (3) a lightfastUV absorber, (4) a lightfast antioxidant, and (5) a colorant, has forexample the following range amounts in embodiments [55+5+10+10+20=100]to [1+97+0.5+0.5+1=about 100], wherein the 55 represents the vehicle,the 5 represents the solid additive, (2) the 10 represents the UVabsorber, the second 10 represents the antioxidant, and the 20represents the colorant.

In preferred embodiments an acid vehicle with for example, a boilingpoint of higher than about 150° C. and preferably between about 170 andabout 300° C. and with for example, an acoustic-loss value of from about5 to about 40 dB/mm is present in an amount of for example, from about50 to about 20 percent by weight, the solid additive aldehyde or acidcompound (2) having a melting point of less than about 75° C. andpreferably with a melting point of between about 35 and about 74° C.,and having an acoustic-loss value of for example, below 100 dB/mm andpreferably from about 25 to about 80 dB/mm is present in an amount offrom about 30 to about 78 percent by weight, the UV absorber is presentin an amount of from about 5 to about 0.5 percent by weight, theantioxidant is present in an amount of from about 5 to about 0.5 percentby weight, and the colorant is present in an amount of from about 10 toabout 1 percent by weight. Amounts within and outside the rangesspecifically indicated may also be selected in embodiments The inkcomposition containing (1) a low acoustic-loss vehicle, (2) a paperadditive, (3) a lightfast UV absorber, (4) a lightfast antioxidant, and(5) a colorant, has the following preferred range amounts in sequencefor (1), (2), (3), (4), and (5): [50+30+5+5+10=100] to[20+78+0.5+0.5+1=100]. These composition ranges were established using astatistical design based on the experimental data of the viscosity at150° C., jettability at 150° C., image quality, lightfastness, andwaterfastness of various compositions.

Embodiments of the present invention include an ink compositioncomprised of a liquid acid vehicle with an acoustic-loss value of fromabout 5 to about 40 dB/mm and a boiling point of greater than about, orequal to about 150° C. and which acid selected from the group consistingof (1) hexanoic acid, (Aldrich #H1,213-7), (2) 5-ketohexanoic acid(Aldrich #A1,320-4), (3) perfluoro heptanoic acid, (Aldrich #34,204-1),(4) octanoic acid, (Aldrich #15,375-3), (5) nonanoic acid, (Aldrich#24,868-1), (6) undecanoic acid, (Aldrich #17,147-6), (7) 2-octenoicacid, (Aldrich #0,520-9), (8) 2-octynoic acid, (Aldrich #28,673-7), and(9) 9hexadecenoic acid, (Aldrich #26,692-3).

Embodiments of the present invention include an ink compositioncomprised of a liquid aldehyde vehicle with an acoustic-loss value offrom about 5 to about 40 dB/mm and having a boiling point of greaterthan about 150° C. and which aldehyde is selected from the groupconsisting of (1) octyl aldehyde, (Aldrich #0,560-8), (2) decylaldehyde, (Aldrich #D22,200-3), (3) dodecyl aldehyde, (Aldrich#D22,200-3), (4) tetradecyl aldehyde, (Aldrich #T1000-6), (5)benzaldehyde, (Aldrich #B1334), (6) 2-chloro benzaldehyde, (Aldrich#12,497-4), (7) 3-chloro benzaldehyde, (Aldrich #C2,340-3), (8) 2-bromobenzaldehyde, (Aldrich #B5,700-1), (9) 3bromo benzaldehyde, (Aldrich#B5,720-6), (10) 3-methoxy benzaldehyde, (Aldrich #12,965-8), (11)4-methoxy benzaldehyde, (Aldrich #A8,810-7), (11) 2-methyl benzaldehyde,(Aldrich #11,755-2), (12) 3-methyl benzaldehyde, (Aldrich #T3,550-5),(13) 4-methyl benzaldehyde, (Aldrich #T3, 560-2), (14) 4acetoxybenzaldehyde, (Aldrich #24,260-8), (15) 4-phenoxy benzaldehyde, (Aldrich#21,126-5), (16) 3-phenoxy benzaldehyde, (Aldrich #19,175-2), (17)2-ethoxy benzaldehyde, (Aldrich #15,372-9), (18) 4-ethoxy benzaldehyde,(Aldrich #17,360-6), (19) 4-butoxybenzaldehyde, (Aldrich #23, 808-2),(20) 2hydroxybenzaldehyde, (Aldrich #S35-6), (21)1,2,3,6-tetrahydrobenzaldehyde, (Aldrich #T1220-3), (22) trans-cinnamaldehyde, (Aldrich#23,996-8), (23) α-chlorocinnamaldehyde, (24)2,3,5,6-tetrafluorobenzaldehyde, (Aldrich #32,893-6), (25) 3-[3-(trifluoromethyl)phenoxy]benzaldehyde, (Aldrich #19,539-1), (26)diphenyl acetaldehyde, (Aldrich#D20,425-0), (27) citral, (Aldrich #C8,300-7), (28)5-methyl-2-phenyl-2-hexenal, (CAS #21834-92-4), (29)2-methyl-3-p-tolylpropion aldehyde, (CAS #6251-78-8), (30) hydroxycitronellal dimethylacetal, (CAS #141-92-4), (31)2,6-dimethyl-5-heptenal, (CAS #106-72-9), and (32) 2-phenylpropionaldehyde, (Aldrich #24,136-9).

In embodiments the present invention relates to inks with a liquid acidvehicle with an acoustic-loss value of from about 5 to about 40 dB/mmand which acid is selected from the group consisting of (1) hexanoicacid, (2) 5-ketohexanoicacid, (3) perfluoro heptanoic acid, (4) octanoicacid, (5) nonanoic acid, (6) undecanoicacid, (7) 2-octenoicacid, (8)2-ctynoicacid, and (9) 9-hexadecenoic acid; wherein the liquid aldehydevehicle with for example, an acoustic-loss value of from about 5 toabout 40 dB/mm is selected from the group consisting of (1) octylaldehyde, (2) decyl aldehyde, (3) dodecyl aldehyde, (4) tetradecylaldehyde, (5) benzaldehyde, (6) 2-chloro benzaldehyde, (7) 3-chlorobenzaldehyde, (8) 2-bromo benzaldehyde, (9) 3-bromo benzaldehyde, (10)3methoxy benzaldehyde, (11) 4-methoxybenzaldehyde, (11)2methylbenzaldehyde, (12) 3-methyl benzaldehyde, (13) 4-methylbenzaldehyde, (14) 4-acetoxy benzaldehyde, (15) 4-phenoxy benzaldehyde,(16) 3-phenoxy benzaldehyde, (17) 2-ethoxybenzaldehyde, (18) 4-ethoxybenzaldehyde, (19) 4-butoxybenzaldehyde, (20) 2-hydroxy benzaldehyde,(21) 1,2,3,6-tetrahydrobenzaldehyde, (22) trans-cinnamaldehyde, (23)α-chlorocinnam aldehyde, (24) 2,3,5,6-tetrafluorobenzaldehyde, (25)3-[3(trifluoromethyl) phenoxy] benzaldehyde, (26) diphenyl acetaldehyde,(27) citral, (28) 5-methyl-2-phenyl-2-hexenal, (29)2-methyl-3polylpropionaldehyde, (30) hydroxycitronellaldimethyl acetal,(31) 2,6-dimethyl-5-heptenal, or (32) 2-phenyl propionaldehyde; whereinthe solid additive with for example, a melting point of from about 35 toabout 74° C. is selected from the group consisting of (1)2-hydroxyhexanoic acid, (2) 6oxoheptanoic acid, (3) 6,8 dithiooctanoicacid, (4) 7-oxooctanoic acid, (5) hepta deca fluoro nonanoic acid, (6)decanoic acid, (7) tridecanoic acid, (8) pentadecanoic acid, (9) heptadecanoic acid, (10) erucic acid, (11) 10-undecynoic acid, (12) nervonicacid, (13) tiglic acid, (14) eladic acid, (15)6(carbobenzyloxyamino)caproic acid, (16) N-carbobenzyloxy-L-isoleucine,(17) N-carbobenzyloxy-2-methylalanine, (18) N-carbobenzyloxy-L-tyrosinehydrate, (19) carbo benzyloxy-L-valine, (20) (N-(tert-butoxycarbonyl)-L-isoleucine, (21) (N-(tert-butoxycarbonyl)-L-methionine, (22)2-bromoacrylic acid, (23) cis-3chloroacrylic acid, (24)3,3-dimethylacrylic acid, (25) 2-(trifluoromethyl) acrylic acid, (26)2,3-dibromopropionic acid, (27) (±)-α-(tert-butyl) hydrocinnamic acid,and (28) trans-2-methyl-2-pentenoicacid; wherein the solid additivealdehyde compound with a melting point of about 35 to about 74° C. isselected from the group consisting of (1) 3-fluoro-p-anisaldehyde, (2)4diethyl amino benzaldehyde, (3) 2-methoxybenzaldehyde, (4)2,3,4trimethoxybenzaldehyde, (5) 3,4-dimethoxy benzaldehyde, (6)3,5-dimethoxy benzaldehyde, (7) 2,3-dimethoxy benzaldehyde, (8)2,5-dimethoxy benzaldehyde, (9) 2,4-dimethoxy-3-methylbenzaldehyde, (10)4-chloro benzaldehyde, (11) 4-bromobenzaldehyde, (12)3-bromo-4,5dimethoxybenzaldehyde, (13) 3-benzyloxy benzaldehyde, (14)2-benzyloxy-3methoxybenzaldehyde, (15)3-benzyloxy-4-methoxybenzaldehyde, (16) 4benzyloxy-3-methoxybenzaldehyde, (17) 3-ethoxy-4-methoxybenzaldehyde, (18)2-hydroxy-3-methoxybenzaldehyde, (19) 2-hydroxy-4-methoxy benzaldehyde,and (20) c-bromo cinnamaldehyde; wherein the lightfastness UV absorbingcompound is selected from the group consisting of (1)2-(2'-hydroxy-5'-methylphenyl) benzotriazole, (2)2-[2'-hydroxy-3,5-di-(1,1-dimethyl benzyl) phenyl]-2H-benzotriazole, (3)bis[2-hydroxy-5-tert-octyl-3-(benzotriazol-2-yl) phenylmethane, (4)2-(3',5'-di-tert-butyl-2'-hydroxyphenyl)5-chlorobenzotriazole, (5)2-(4-benzoyl-3-hydroxyphenoxy)ethylacrylate), (6)tris(3,5-di-tert-butyl-4-hydroxy benzyl)isocyanurate, wherein thelightfast antioxidant compound is selected from the group consisting of(1) bis(1,2,3,6-tetrahydrobenzaldehyde) pentaerythritol acetal, (2)dioctadecyl 3,3'-thio dipropionate, (3)2,2,4-trimethyl-1,2-hydroquinoline, (4) octylated diphenylamine, (5)N,N'-β,β'-naphthalene-p-phenylenediamine, (6)ethyl(R)(+)-2-{4-[trifluoromethyl) phenoxy]phenoxy}propionate, and (7)3-hydroxy-2,2dimethylpropyl-3-hydroxy-2,2-dimethylpropionate; or whereinthe solid additive acid compound with a melting point of less than 75°C. and preferably from about 35 to about 74° C. and with anacoustic-loss value of below 100 dB/mm and preferably from about 25 toabout 80 dB/mm include (1) 2-hydroxyhexanoicacid, (Aldrich #21,980-0),(2) 6-oxoheptanoic acid, (Aldrich #39,936-1), (3) 6,8 dithiooctanoicacid, (Aldrich #T2,860-6), (4) 7oxooctanoic acid, (Aldrich #34,362-5),(5) hepta deca fluoro nonanoic acid, (Aldrich #39,445-9), (6) decanoicacid, (Aldrich #D165-3), (7) tridecanoic acid, (Aldrich #T5,760-6), (8)pentadecanoic acid, (Aldrich #P360-0), (9) hepta decanoic acid, (Aldrich#H100-0), (10) erucic acid, (Aldrich #85,8439), (11) 10-undecynoic acid,(Aldrich #40,654-6), (12) nervonic acid, (Aldrich #28,682-6), (13)tiglic acid, (Aldrich #T3,520-3), (14) eladic acid, (Aldrich #E30-4),(15) 6-(carbobenzyloxyamino) caproicacid, (Aldrich #29,952-9), (16)N-carbobenzyl oxy-L-isoleucine, (Aldrich #40,853-0), (17)N-carbobenzyloxy-2-methylalanine, (Aldrich #37,094-0), (18)N-carbobenzyloxy-L-tyrosinehydrate, (Aldrich #40, 849-2), (19)carbobenzyloxy-L-valine, (Aldrich #29,352-0), (20) (N-(tert-butoxycarbonyl)-L-isoleucine, (Aldrich #40,853-0), (21)(N-(tert-butoxycarbonyl)-L-methionine, (Aldrich #40,842-5), (22)2-bromoacrylicacid, (Aldrich #33,842-7), (23) cis-3-chloroacrylic acid,(Aldrich #17,740-7), (24) 3,3-dimethylacrylic acid, (Aldrich#D13,860-6), (25) 2-(trifluoromethyl)acrylicacid, (Aldrich #36,914-4),(26) 2,3-dibromo propionic acid, (Aldrich #13,994-7), (27)(±)-α-(tert-butyl) hydrocinnamic acid, (Aldrich #34, 002-2), or (28)fresh fruit flavor compounds such as trans-2-methyl-2-pentenoic acid,(Aldrich #26,477-6).

The solid additive aldehyde compounds with for example, a melting pointof less than, or equal to about 75° C. and preferably from about 35 toabout 74° C. and preferably an acoustic-loss value of less than 100dB/mm and preferably from about 25 to about 80 dB/mm include: (1)3fluoro-p-anisaldehyde, (Aldrich #15,558-6), (2) 4-diethyl aminobenzaldehyde, (Aldrich #D8,625-6), (3) 2-methoxy benzaldehyde, (Aldrich#10,962-2), (4) 2,3,4-trimethoxy benzaldehyde, (Aldrich #15,209-9), (5)3,4-dimethoxy benzaldehyde, (Aldrich #14,375), (6) 3,5-dimethoxybenzaldehyde, (Aldrich #12,629-2), (7) 2,3-dimethoxy benzaldehyde,(Aldrich #D13,020-6), (8) 2,5-dimethoxy benzaldehyde, (Aldrich#D13,060-5), (9) 2,4-dimethoxy-3-methylbenzaldehyde, (Aldrich#29,627-9), (10) 4-chlorobenzalde hyde, (Aldrich #11,221-6), (11)4-bromobenzaldehyde, (Aldrich #B5,740-0), (12)3bromo-4,5-dimethoxybenzaldehyde, (Aldrich #13,061-3), (13) 31benzyloxybenz aldehyde, (Aldrich #B2,700-5), (14) 2-benzyloxy-3-methoxybenzaldehyde, (Aldrich #43,479-5), (15) 3-benzyloxy-4-methoxybenzaldehyde, (Aldrich #16,395-3), (16) 4-benzyloxy-3-methoxybenzaldehyde, (Aldrich #16,361-9), (17) 3-ethoxy-4-methoxy benzaldehyde,(Aldrich #25,275-1), (18) 2-hydroxy-3-methoxybenzaldehyde, (Aldrich#1208-4), (19) 2-hydroxy-4-methoxy benzaldehyde, (Aldrich #16,069-2),(20) α-bromo cinnamaldehyde, (Aldrich #16,116-0), (21) vanilla flavorcompounds such as ethyl vanillin, (Aldrich #12,809-0), and the like.

The lightfast UV absorbers in the ink composition include for example,(1) 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, available as Tinuvin900, from Ciba Geigy Corporation; (2)2-[2'-hydroxy-3,5-di-(1,1-dimethylbenzyl)phenyl]-2H-benzotriazole,available as Topanex 100 BT, from ICI America Corporation; (3)bis[2-hydroxy-5-tert-octyl-3-(benzotriazol-2-yl) phenyl methane,available as Mixxim BB/100, from Fairmount-Corporation; (4)2-(3',5'-di-tert-butyl-2'-hydroxyphenyl)-5-chlorobenzo triazole,available as Tinuvin 327, from Ciba Geigy Corporation; (5)2-(4-benzoyl-3hydroxyphenoxy)ethylacrylate (Cyasorb UV-416, #41,321-6,available from Aldrich Chemical Company), (6)tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, available asGood-rite UV 3114, from Goodrich Chemicals, and the like.

The lightfast antioxidants of the ink compositions include for example:(1) bis-(1,2,3,6-tetrahydrobenzaldehyde) pentaerythritol acetal,available as Vulkazon AFS/IG, from Mobay Corporation; (2) dioctadecyl3,3'-thiodipropionate, available as Cyanox, STDP, #41,310-0, fromAldrich Chemical Company; (3) 2,2,4-trimethyl-1,2-hydroquinoline,available as Vulkanox HS, from Mobay Corporation; (4) octylateddiphenylamine, available as Anchor ODPA, from Anchor Corporation; (5)N,N'-β,β'-naphthalene-ρ-phenylenediamine, available as Anchor DNPD, fromAnchor Corporation; (6) ethyl(R)-(+)-2-{4-[trifluoromethyl)phenoxy]phenoxy}propionate, (Aldrich #25,074-0); (7)3-hydroxy-2,2-dimethylpropyl-3-hydroxy-2,2-dimethylpropionate, (Aldrich#39,024-0), and the like.

Suitable colorants, present in an effective amount generally of fromabout 1 to about 25, and for example from about 2 to about 12 percent byweight, include pigments and dyes, pigments, dyes, mixtures of pigments,mixtures of dyes, and the like with solvent dyes being preferred. Anydye or pigment may be selected providing for example that it is capableof being dispersed or dissolved in the vehicle and is compatible withthe other ink components.

Examples of suitable pigments include Violet Toner VT-8015 (PaulUhlich), Paliogen Violet 5100 (BASF), Paliogen Violet 5890 (BASF),Permanent Violet VT 2645 (Paul Uhlich), Heliogen Green L8730 (BASF),Argyle Green XP-111-S (Paul Uhlich), Brilliant Green Toner GR 0991 (PaulUhlich), Lithol Scarlet D3700 (BASF), Toluidine Red (Aldrich), Scarletfor Thermoplast NSD PS PA (Ugine Kuhlmann of Canada), E. D. ToluidineRed (Aldrich), Lithol Rubine Toner (Paul Uhlich), Lithol Scarlet 4440(BASF), Bon Red C (Dominion Color Company), Royal Brilliant Red RD-8192(Paul Uhlich), Oracet Pink RF (Ciba-Geigy), Paliogen Red 3871 K (BASF),Paliogen Red 3340 (BASF), Lithol Fast Scarlet L4300 (BASF), HeliogenBlue L6900, L7020 (BASF), Heliogen Blue K6902, K6910 (BASF), HeliogenBlue D6840, D7080 (BASF), Sudan Blue OS (BASF), Neopen Blue FF4012(BASF), PV Fast Blue B2G01 (American Hoechst), Irgalite Blue BCA(Ciba-Geigy), Paliogen Blue 6470 (BASF), Sudan III (Red Orange),(Matheson, Colemen Bell), Sudan II (Orange), (Matheson, Colemen Bell),Sudan Orange G (Aldrich), Sudan Orange 220 (BASF), Paliogen Orange 3040(BASF), Ortho Orange OR 2673 (Paul Uhlich), Paliogen Yellow 152,1560(BASF), Lithol Fast Yellow 0991K (BASF), Paliotol Yellow 1840 (BASF),Novoperm Yellow FGL (Hoechst), Permanent Yellow YE 0305 (Paul Uhlich),Lumogen Yellow D0790 (BASF), Suco-Yellow L1250 (BASF), Suco-Yellow D1355(BASF), Suco Fast Yellow D1355, D1351 (BASF), Hostaperm Pink E (AmericanHoechst), Fanal Pink D4830 (BASF), Cinquasia Magenta (Du Pont), PaliogenBlack L0084 (BASF), Pigment Black K801 (BASF), and carbon blacks such asRegal 330 ® (Cabot), Carbon Black 5250, Carbon Black 5750 (ColumbiaChemical Company).

Examples of suitable dyes include Pontamine; Food Black 2; CarodirectTurquoise FBL Supra Conc. (Direct Blue 199), available from CarolinaColor and Chemical; Special Fast Turquoise 8 GL Liquid (Direct Blue 86),available from Mobay Chemical; Intrabond Liquid Turquoise GLL (DirectBlue 86), available from Crompton and Knowles; Cibracron Brilliant Red38-A (Reactive Red 4), available from Aldrich Chemical; DrimareneBrilliant Red X2B (Reactive Red 56), available from Pylam, Inc.; LevafixBrilliant Red E-4B, available from Mobay Chemical; Levafix Brilliant RedE6-BA, available from Mobay Chemical; Procion Red H8B (Reactive Red 31),available from ICI America; Pylam Certified D&C Red #28 (Acid Red 92),available from Pylam; Direct Brill Pink B Ground Crude, available fromCrompton and Knowles; Cartasol Yellow GTF Presscake, available fromSandoz, Inc.; Tartrazine Extra Conc. (FD&C Yellow #5, Acid Yellow #23),available from Sandoz, Inc.; Carodirect Yellow RL (Direct Yellow 86),available from Carolina Color and Chemical; Cartasol Yellow GTF LiquidSpecial 110, available from Sandoz, Inc.; D&C Yellow #10 (Acid Yellow3), available from Tricon; Yellow Shade 16948, available from Tricon;Basacid Black×34, available from BASF; Carta Black 2GT, available fromSandoz, Inc.; and the like.

Particularly preferred are solvent dyes, and within the class of solventdyes, spirit soluble dyes are preferred primary because of theircompatibility with the ink vehicles. Examples of suitable spirit solventdyes include Neozapon Red 492 (BASF), Orasol Red G (Ciba-Geigy), DirectBrilliant Pink B (Crompton-Knolls), Aizen Spilon Red C-BH (HodagayaChemical Company), Kayanol Red 3BL (Nippon Kayaku Company). LevanolBrilliant Red 3BW (Mobay Chemical Company), Levaderm Lemon Yellow (MobayChemical Company), Spirit Fast Yellow 3G, Aizen Spilon Yellow GGNH(Hodagaya Chemical Company), Sirius Supra Yellow GD 167, CartasolBrilliant Yellow 4GF (Sandoz), Pergasol Yellow CGP (Ciba-Geigy), OrasolBlack RLP(Ciba-Geigy), Savinyl Black RLS (Sandoz), Dermacarbon2GT(Sandoz), Pyrazol Black BG (ICI), Morfast Black Conc.A(Morton-Thiokol), Diaazol Black RN Quad (ICI),Orasol Blue GN(Ciba-Geigy), Savinyl Blue GLS (Sandoz), Luxol Blue MBSN(Morton-Thiokol), Sevron Blue 5GMF (ICI),Basacid Blue 750 (BASF), andthe like.

Optional ink additives include biocides such as Dowicil 150, 200, and75, benzoate salts, sorbate salts, and the like, present in effectiveamounts, such as for example an amount of from about 0.0001 to about 2percent by weight, and preferably from about 0.01 to about 1.0 percentby weight. The amount of biocide is generally present in amounts of fromabout 10 to 25 milligrams per one gram of ink. Other ink additives, suchas humectants, and the like can also be incorporated into the inks.

The vehicle may be comprised of a mixture of the acid, and the aldehyde,and which mixture contains for example, form about 1 to about 99 weightpercent or parts of each component, and preferably from about 40 toabout 60 weight percent of each component. Acids for the vehicle includehydroxy acids, such as 12-hydroxystearic acid, 12-hydroxydodecanoicacid, and the like, and 2-acetoxysuccinic anhydride, 2hydroxy N-methylsuccinimide, and the like.

The inks of the present invention can be prepared by any suitablemethod. A colored semi-solid hot melt ink composition can be prepared byfor example, mixing 46 percent by weight of a liquid vehicle with anacoustic-loss value of about 5 to about 40 dB/mm and a boiling point ofgreater than 150° C., 42 percent by weight of a solid additive with amelting point of lower than 75° C. and an acoustic-loss value of lessthan about 100 dB/mm, 3 percent by weight of a lightfast UV absorber, 3percent by weight of lightfast antioxidant and 6 percent by weight of acolorant. The mixture is then heated to a temperature of about 100° C.and stirred for a period of about 60 minutes until it forms ahomogeneous solution, and subsequently it is cooled to 25° C.

The inks of the present invention are particularly suitable for printingprocesses wherein the substrate, such as plain paper, coated paper,transparency, or the like, is heated during the printing process tofacilitate formation of the liquid crystalline phase within the ink.When transparency substrates are employed, temperatures typically arelimited to a maximum of about 100° C. to about 110° C., since thepolyester typically employed as the base sheet in transparency sheetstends to deform at higher temperatures specially formulatedtransparencies and paper substrates can, however, tolerate highertemperatures, and frequently are suitable for exposure to temperaturesof 150° C. or even 200° C. in some instances. Typical heatingtemperatures are from about 40° C. to about 140° C., and preferably fromabout 60° C. to about 95° C., although the temperature can be outsidethese ranges.

The inks of the present invention are also suitable for use in acousticink jet printing processes. In acoustic ink jet printing, reference anumber of the copending applications and patents recited here, thedisclosures of which have been totally incorporated herein by reference,an acoustic beam exerts a radiation pressure against objects upon whichit impinges. Thus, when an acoustic beam impinges on a free surface ofthe ink of a pool of liquid from beneath, the radiation pressure whichit exerts against the surface of the pool may reach a sufficiently highlevel to release individual droplets of liquid from the pool, despitethe restraining force of surface tension. Focusing the beam on or nearthe surface of the pool intensifies the radiation pressure it exerts fora given amount of input power, reference, for example, IBM TechnicalDisclosure Bulletin, Vol. 16, No. 4, September 1973, pages 1168 to 1170,the disclosure of which is totally incorporated herein by reference.Acoustic ink printers typically comprise one or more acoustic radiatorsfor illuminating the free surface of a pool of liquid ink withrespective acoustic beams. Each of these beams usually is brought tofocus at or near the surface of the reservoir (i.e., the liquid/airinterface). Furthermore, printing conventionally is performed byindependently modulating the excitation of the acoustic radiators inaccordance with the input data samples for the image that is to beprinted. This modulation enables the radiation pressure, which each ofthe beams exerts against the free ink surface, to make brief, controlledexcursions to a sufficiently high pressure level for overcoming therestraining force of surface tension. That, in turn, causes individualdroplets of ink to be ejected from the free ink surface on demand at anadequate velocity to cause them to deposit in an image configuration ona nearby recording medium. The acoustic beam may be intensity modulatedor focused/defocused to control the ejection timing, or an externalsource may be used to extract droplets from the acoustically excitedliquid on the surface of the pool on demand. The size of the ejecteddroplets is determined by the waist diameter of the focused acousticbeam. Acoustic ink printing is attractive because it does not requirethe nozzles or the small ejection orifices which have caused many of thereliability and pixel placement accuracy problems that conventional dropon demand and continuous stream ink jet printers have suffered.

Pixel placement accuracy problems that conventional drop on demand andcontinuous stream ink jet printers have suffered. The size of theejection orifice is a critical design parameter of an ink jet because itdetermines the size of the droplets of ink that the jet ejects. As aresult, the size of the ejection orifice cannot be increased withoutsacrificing resolution. Acoustic printing has increased intrinsicreliability since usually there are no nozzles to clog. Furthermore,small ejection orifices are avoided, so acoustic printing can beperformed with a greater variety of inks than conventional ink jetprinting, including inks having higher viscosity's and inks containingpigments and other particulate components. Acoustic ink printersembodying printheads comprising acoustically illuminated sphericalfocusing lenses can print precisely positioned pixels (picture elements)at resolutions which are sufficient for high quality printing ofrelatively complex images. It has also been determined that the size ofthe individual pixels printed by such a printer can be varied over asignificant range during operation, thereby accommodating, for example,the printing of variably shaded images. Furthermore, the known dropletejector technology can be adapted to a variety of printheadconfigurations, including (1) single ejector embodiments for raster scanprinting, (2) matrix configured ejector arrays for matrix printing, and(3) several different types of page width ejector arrays, ranging from(i) single row, sparse arrays for hybrid forms of parallel/serialprinting to (ii) multiple row staggered arrays with individual ejectorsfor each of the pixel positions or addresses within a page width imagefield (i.e., single ejector/pixel/line) for ordinary line printing. Inkssuitable for acoustic ink jet printing typically are liquid at ambienttemperatures (i.e., about 250C), however in other embodiments the ink isin a solid state at ambient temperatures and provision is made forliquefying the ink by heating or any other suitable method prior tointroduction of the ink into the printhead. Images of two or more colorscan be generated by several methods, including by processes wherein asingle printhead launches acoustic waves into pools of different coloredinks. Further information regarding acoustic ink jet printing apparatusand processes is disclosed in, for example, U.S. Pat. No. 4,308,547,U.S. Pat. No. 4,697,195, U.S. Pat. No. 5,028,937, U.S. Pat. No.5,041,849, U.S. Pat. No. 4,751,529, U.S. Pat. No. 4,751,530, U.S. Pat.No. 4,751,534, U.S. Pat. No. 4,801,953, and U.S. Pat. No. 4,797,693, thedisclosures of each of which are totally incorporated herein byreference. The use of focused acoustic beams to eject droplets ofcontrolled diameter and velocity from a free-liquid surface is alsodescribed in J. Appl. Phys., vol. 65, no. 9 (1 May 1989) and referencestherein, the disclosure of which is totally incorporated herein byreference.

Acoustic-loss Measurements recited herein were measured as follows:samples of various liquid vehicles and solid additives (2) or surfaceleveling compounds were placed between the two transducers with thetemperature set at 150° C. The samples were allowed to equilibrate at150° C. for five minutes. The two transducers were brought together tomaximize the acoustic signal. The amplitude and the position of thesignals were recorded. The two transducers were separated by a distancevarying from 25.4 microns to 125.4 microns recording each time theamplitude and the position of the signal. Each measurement was performedthree times and three samples of the same material were measured. Theattenuation dB/mm was then calculated by ratioing the amplitude valuesobtained at different separation distances. The liquid acids and liquidaldehydes had dB/mm values of for example, from about 20 to 40, whereasthe solid acids and aldehydes had dB/mm values of for example, of fromabout 40 to about 55.

The optical density measurements recited herein were obtained on aPacificpectrograph Color System. The system consists of two majorcomponents, an optical sensor and a data terminal. The optical sensoremploys a 6 inch integrating sphere to provide diffuse illumination and8 degrees viewing. This sensor can be used to measure both transmissionand reflectance samples. When reflectance samples are measured, aspecular component may be included. A high resolution, full dispersion,grating monochromator was used to scan the spectrum from 380 to 720nanometers. The data terminal features a 12 inch CRT display, numericalkeyboard for selection of operating parameters and the entry oftristimulus values, and an alphanumeric keyboard for entry of productstandard information The lightfast values of the ink jet images weremeasured in the Mark V Lightfast Tester obtained from Microscal Company,London, England.

The waterfast values of the ink jet images were obtained from theoptical density data recorded before and after washing with hot [50° C.]water for two minutes.

Water may be selected for the inks of the present invention, howeverpreferably little or no water is present.

Specific embodiments of the invention will now be described in detail.These examples are intended to be illustrative, and the invention is notlimited to the materials, conditions, or process parameters set forth inthese embodiments. All parts and percentages are by weight unlessotherwise indicated.

EXAMPLE 1

A black semi-solid hot melt ink composition was prepared by mixing 46percent by weight of the liquid vehicle hexanoic acid, (Aldrich#H1,213-7), with an acoustic-loss value of 25 dB/mm and a boiling pointof 202° C., 42 percent by weight of the solid acid (2) additive2hydroxyhexanoic acid, (Aldrich #21,980-0), having a melting point of62° C. (Centigrade throughout) and an acoustic-loss value of 40 dB/mm, 3percent by weight of the UV absorber2-(4-benzoyl-3-hydroxyphenoxy)ethylacrylate (Cyasorb UV-416, #41,321-6,Aldrich Chemical Company) melting point 780C, 3 percent by weight of theantioxidant 3-hydroxy-2,2-dimethylpropyl-3hydroxy-2,2-dimethylpropionate, (Aldrich #39,024-0), melting point 52° C., and 6 percent byweight of the colorant Orasol Black RLP (Ciba-Geigy). The resultingmixture was heated to a temperature of about 100° C. and stirred for aperiod of about 60 minutes until it formed a homogeneous solution, andsubsequently the mixture was cooled to 25° C. The resulting black inkpossessed an acoustic loss value of 45 dB/mm and a viscosity of 5 cps at150° C.

EXAMPLE 2

A blue semi-solid hot melt ink composition was prepared by mixing 46percent by weight of the liquid vehicle nonanoic acid, (Aldrich #24,868-1), with an acoustic-loss value of 30 dB/mm and a boiling point of2540C, 42 percent by weight of (2) the solid acid additive pentadecanoicacid, (Aldrich #P360-0) and with a melting point of 52° C. and anacoustic-loss value of 45 dB/mm, 3 percent by weight of the UV absorber2-(4benzoyl-3-hydroxy phenoxy)ethylacrylate (Cyasorb UV-416, #41,321-6,Aldrich Chemical Company) melting point 78° C., 3 percent by weight ofthe antioxidant dioctadecyl-3,3'-thiodipropionate, (Cyanox,STDP,#41,310-0, Aldrich Chemical), melting point 66° C., and 6 percent byweight of the colorant Sudan Blue dye (BASF).The mixture was heated to atemperature of about 100° C. and stirred for a period of about 60minutes until it formed a homogeneous solution, and subsequently wascooled to 25° C. The resulting blue ink had an acoustic loss value of 45dB/mm and a viscosity of 5.2 cps at 150° C.

EXAMPLE 3

A yellow semi-solid hot melt ink composition was prepared by mixing 46percent by weight of the liquid acid vehicle 5-ketohexanoic acid,(Aldrich #A1,320-4) with an acoustic-loss value of 32 dB/mm and aboiling point of 275° C., 42 percent by weight of the solid acidadditive 6,8 dithiooctanoic acid, (Aldrich #T2,860-6), having a meltingpoint of 60° C. and an acoustic-loss value of 42 dB/mm, 3 percent byweight of the UV absorber 2-(4-benzoyl-3-hydroxyphenoxy)ethylacrylate(Cyasorb UV-416, #41,321-6, Aldrich Chemical Company) melting point 78°C., 3 percent by weight of the antioxidant3-hydroxy-2,2-dimethylpropyl-3-hydroxy-2,2dimethylpropionate, (Aldrich#39,024-0), melting point 520C, and 6 percent by weight of the colorantSudan yellow dye (BASF). The resulting mixture was heated to atemperature of about 100° C. and then stirred for a period of about 60minutes until it formed a homogeneous solution, and subsequently wascooled to 25° C. The resulting yellow ink had an acoustic loss value of48 dB/mm and a viscosity of 4.5. cps at 150° C.

EXAMPLE 4

A red semi-solid hot melt ink composition was prepared by mixing 46percent by weight of the liquid vehicle octanoic acid, (Aldrich#15,375-3), with an acoustic-loss value of 28 dB/mm and a boiling pointof 237° C., 42 percent by weight of the additive tiglic acid, (Aldrich#T3,520-3), with a melting point of 62° C. and an acoustic-loss value of45 dB/mm, 3 percent by weight of the UV absorber 2-(4-benzoyl-3-hydroxyphenoxy)ethylacrylate (Cyasorb UV-416, #41,321-6, (Aldrich) meltingpoint 78° C., 3 percent by weight of the antioxidant3-hydroxy-2,2-dimethylpropyl-3hydroxy-2,2-dimethylpropionate (Aldrich#39,024-0), melting point 52° C., and 6 percent by weight of thecolorant Sudan Red dye (BASF). The mixture resulting was heated to atemperature of about 100° C. and stirred for a period of about 60minutes until it formed a homogeneous solution, and subsequently wascooled to 25° C. The resulting red ink had an acoustic loss value of 45dB/mm and a viscosity of 5.2 cps at 150° C.

Each of the above four prepared inks were incorporated into an acousticink jet printing test fixture utilizing the ejection mechanism disclosedin J. Appl. Phys. 65(9), May 1, 1989, and references therein, thedisclosure of which are totally incorporated herein by reference. Ajetting frequency of 160 MHz was used to generate drops of about 2picoliters, up to 12 drops per pixel at 600 spi. The images formedexhibited excellent color quality with optical density values of 1.6(Black), 1.6 (Cyan), 1.35 (Magenta ), 0.9 (Yellow), and sharp edges,with lightfastness and waterfastness of about 99.5 percent.

EXAMPLE 5

A black semi-solid hot melt ink composition was prepared by mixing 46percent by weight of the liquid vehicle decyl aldehyde, (Aldrich#D22,200-3) having an acoustic-loss value of 30 dB/mm and a boilingpoint of 208° C., 42 percent by weight of the solid additive4-benzyloxy-3-methoxy benzaldehyde, (Aldrich #16,361-9), having amelting point of 65° C. and an acoustic-loss value of 40 dB/mm, 3percent by weight of the UV absorber2(4-benzoyl-3-hydroxyphenoxy)ethylacrylate (Cyasorb UV-416, #41,321-6,Aldrich Chemical Company) melting point 78° C., 3 percent by weight ofthe antioxidant 3-hydroxy-2,2-dimethylpropyl-3-hydroxy-2,2-dimethylpropionate, (Aldrich #39, 024-0), melting point 52° C., and 6 percent byweight of the colorant Orasol Black RLP (Ciba-Geigy). The resultingmixture was heated to a temperature of about 100° C. and stirred for aperiod of about 60 minutes until it formed a homogeneous solution, andsubsequently it was cooled to 25° C. The resulting black ink had anacoustic loss value of 46 dB/mm and a viscosity of 5 cps at 150° C.

EXAMPLE 6

A blue semi-solid hot melt ink composition was prepared by mixing 46percent by weight of the liquid vehicle 2,3,5,6-tetrafluorobenzaldehyde, (Aldrich #32,893-6), with an acoustic-loss value of 25dB/mm and a boiling point of 178° C., 42 percent by weight of the solidadditive 3benzyloxy-4-methoxy benzaldehyde, (Aldrich #16,395-3), with amelting point of 63° C. and an acoustic-loss value of 42 dB/mm, 3percent by weight of the UV absorber2-(4-benzoyl-3-hydroxyphenoxy)ethylacrylate (Cyasorb UV-416, #41,321-6,Aldrich) melting point 78° C., 3 percent by weight of the antioxidantdioctadecyl-3,3'-thiodipropionate, (Cyanox, STDP, #41,310-0, (Aldrich),melting point 66° C., and 6 percent by weight of the colorant Sudan Bluedye (BASF). The mixture was then heated to a temperature of about 100°C. and stirred for a period of about 60 minutes until it formed ahomogeneous solution, and subsequently was cooled to 25° C. Theresulting blue ink had an acoustic loss value of 42 dB/mm and aviscosity of 5.1 cps at 150° C.

EXAMPLE 7

A yellow semi-solid hot melt ink composition was prepared by mixing 46percent by weight of the liquid vehicle decyl aldehyde, (Aldrich#D22,200-3) with an acoustic-loss value of about 30 dB/mm and a boilingpoint of 208° C., 42 percent by weight of the (2) solid paper surfaceleveling agent 4-benzyloxy-3-methoxy benzaldehyde, (Aldrich #16,361-9),having a melting point of 65° C. and an acoustic-loss value of dB/mm, 3percent by weight of the UV absorber 2-(4-benzoyl-3-hydroxyphenoxy)ethylacrylate (Cyasorb UV-416, #41,321-6, Aldrich Chemical Company)melting point 78° C., 3 percent by weight of the antioxidant3-hydroxy-2,2-dimethylpropyl-3hydroxy-2,2-dimethyl propionate , (Aldrich#39,024-0), melting point 52° C., and 6 percent by weight of thecolorant Sudan yellow dye (BASF). The mixture resulting was heated to atemperature of about 100° C. and stirred for a period of about 60minutes until it formed a homogeneous solution, and subsequently it wascooled to 25° C. The resulting yellow ink had an acoustic loss value of47 dB/mm and a viscosity of 5.1 cps at 150° C.

EXAMPLE 8

A red semi-solid hot melt ink composition was prepared by mixing 46percent by weight of the liquid vehicle 2,3,5,6-tetrafluorobenzaldehyde, (Aldrich #32,893-6), with an acoustic-loss value of 25dB/mm and a boiling point of 178° C., 42 percent by weight of theadditive 3-benzyloxy-4-methoxy benzaldehyde, (Aldrich #16,395-3), with amelting point of 63° C. and an acoustic-loss value of 42 dB/mm, 3percent by weight of the UV absorber2-(4-benzoyl-3-hydroxyphenoxy)ethylacrylate (Cyasorb UV-416, #41,321-6,Aldrich) melting point 78° C., 3 percent by weight of the antioxidantdioctadecyl 3,3'-thiodipropionate, (Cyanox,STDP, #41,310-0, Aldrich),melting point 66° C., and 6 percent by weight of the colorant Sudan Reddye (BASF). The resulting mixture was heated to a temperature of about100° C. and stirred for a period of about 60 minutes until it formed ahomogeneous solution, and it was cooled to 25° C. The resulting red inkhad an acoustic loss value of 45 dB/mm and a viscosity of 5 cps at 150°C.

Each of the above four inks were incorporated into an acoustic ink jetprinting test fixture utilizing the ejection mechanism disclosed in J.Appl. Phys. 65(9), May 1, 1989, and references therein, the disclosureof which are totally incorporated herein by reference. A jettingfrequency of 160 MHz was used to generate drops of about 2 picoliters,up to 12 drops per pixel at 600 spi. The images formed exhibitedexcellent color quality with optical density values of 1.55 (Black),1.65 (Cyan), 1.30 (Magenta ), 0.9 (Yellow), and sharp edges, withlightfastness and waterfastness for the images of 98 percent for all theinks.

Other modifications of the present invention may occur to those ofordinary skill in the art subsequent to a review of the presentapplication, and these modifications, including equivalents thereof, areintended to be included within the scope of the present invention.

What is claimed is:
 1. An ink comprised of (1) a liquid aldehyde, aliquid acid, or mixtures thereof, (2) a solid additive aldehydecompound, a solid additive acid compound, or mixtures thereof, (3) alightfastness UV absorber, (4) a lightfastness antioxidant, and (5) acolorant.
 2. An ink in accordance with claim 1 wherein (1) possesses anacoustic-loss value of from about 5 to about 40 dB/mm, and (2) possessesa melting point of from about 35 to about 74° C.
 3. An ink in accordancewith claim 1 wherein the colorant is a pigment.
 4. An ink in accordancewith claim 1 wherein (1) is an acid vehicle.
 5. An ink in accordancewith claim 1 wherein (1) is an aldehyde vehicle.
 6. An ink comprised of(1) a liquid aldehyde, a liquid acid, or mixtures thereof, (2) a solidadditive aldehyde compound, a solid additive acid compound, (3) alightfastness component, (4) a lightfastness antioxidant, and (5) acolorant.
 7. An ink in accordance with claim 6 which possesses a meltingpoint of from about 25° C. to about 50° C.
 8. An ink compositioncomprised of a liquid vehicle with an acoustic loss value of from about5 to about 40 db/mm, a solid additive which possesses a melting point offrom about 35° C. to about 74° C., a lightfastness component and acolorant.